1. Field of the Invention
The present invention relates to an illumination system and a projection apparatus adopting the illumination system, and more particularly, to an illumination system that uses a curved reflecting component in combination with a polarizer and a half wave retarder.
2. Descriptions of the Related Art
Over recent years, digital light processing (DLP) projection systems have found a wide application in projection apparatuses because of their advantages, such as a high brightness, realistic colors, a rapid response speed and a light weight. Aside from DLP projection systems that are generally used to display two-dimensional (2D) images, there are also DLP projection systems used to display stereoscopic images.
DLP projection systems for displaying stereoscopic images are generally divided into the eyeglass type and the auto-stereoscopic type. DLP projection systems of the eyeglass type have a low production cost and have been widely used since the advent thereof. According to the conventional stereoscopic projection technology of the eyeglass type, two projectors are arranged in a row to simulate images visible to the left eye and the right eye of a viewer respectively and a polarizer is installed in front of each of the projectors. By adjusting positions at which images are projected to the left eyeglass and the right eyeglass, different images will be seen at the imaging positions by the left eye and the right eye respectively, thus achieving a stereoscopic displaying effect.
However, in order to have the images projected by the two projectors overlapped at a same position, the two projectors must be aligned precisely. Therefore, when service locations of the projectors are changed, alignment of the two projectors must be calibrated and adjusted anew. Furthermore, use of the two projectors not only occupies a large space but also leads to a high cost.
Accordingly, an urgent need exists in the art to design a stereoscopic image projection apparatus that can be used with a pair of passive eyeglasses and that has a low cost, a simplified optical arrangement and a miniaturized volume.